Fluorescent Mineral Database

A new secret project! Trying to create a nice Fluorescent Mineral Database (FMDB), which would be searchable by mineral, locality, and luminescence properties. Also making it easy for people to contribute with their own specimens!

Witherite - Cave-In-Rock, Illinois

Contributed by: Chris Clemens
Date: Apr 30th, 2026
Locality: Cave-in-Rock, Cave-In-Rock Mining Sub-District, Hardin County, Illinois, USA (See on Mindat)
Size: 71 x 49 x 75 mm
Weight: 302 g

Description:
Witherite is a relatively rare barium carbonate mineral that shows a blue/white, fluorescent response under shortwave and longwave UV. The historical fluorspar (fluorite) mines of Cave-In-Rock, Hardin County, Illinois, have produced specimens of witherite of exceptional quality. This specimen consists of a mass of large, twinned (pseudohexagonal) crystals of off-white witherite on a minimal matrix of unknown grey material. The witherite shows a similar fluorescent response under all UV wavelengths- glowing blue/white, slightly warmer under longwave. This specimen also shows green phosphorescence, most brightly following shortwave UV.

Originally posted by Chris Clemens on Nature's Rainbows in 2017.

Fluorescence under shortwave UV light.
Fluorescence under shortwave UV light.
Afterglow after exposure to shortwave UV light.
Afterglow after exposure to shortwave UV light.
Fluorescence under longwave UV light.
Fluorescence under longwave UV light.
Normal light.
Normal light.

Summary of luminescence responses:

Witherite (Mindat) (RRUFF)

  • Fluorescence under Longwave (365nm LED) UV light: White
  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: White
  • Afterglow after exposure to Shortwave (254nm Lamp/Mercury) UV light: Green

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